What is threonine?
Threonine (pronounced three-uh-neen) is an essential amino acid. If you recall our earlier blog, A Quick Guide to Amino Acids, you will remember that essential amino acids are unable to be manufactured within the body. Thus, they are “essential” to consume in our diet. This particular essential amino acid is commonly found in lean beef, chicken, tuna, tofu, beans, milk, eggs, and nuts. It aids in maintaining the protein balance within our bodies.
Why is threonine important?
Threonine is best known for its ability to stretch and protect. While it has many functions within the body, it is arguably most important for the formation of collagen (a protein responsible for healthy joints and skin elasticity), elastin (the protein that helps organs and connective tissue to stretch), and tooth enamel (the outer protective layer of teeth).
Threonine is required to produce proper functioning collagen and elastin proteins. Many of us have heard of collagen, but did you know that it is the most abundant protein in the body? It has a presence in our muscles, bones, skin, blood vessels, tendons, and digestive systems. Unfortunately, as we age, collagen degrades, making our ability to produce it even more important. Thus, by consuming threonine, we can help to support collagen production and care for our muscles, bones, skin, etc.
Threonine also helps to keep connective tissues throughout the body strong and elastic. One particularly important organ that threonine helps is the heart. The heart’s ability to stretch and return to its original form allows it to properly function.
Not only is threonine a powerful amino acid on its own, it also helps to form other important amino acids (glycine and serine). Glycine is only made in small amounts by the body, giving it a classification as a conditionally essential amino acid. This means that most of our glycine supply is consumed directly in our diet or we consume the precursor to glycine (like threonine) and our bodies convert the threonine to glycine. Glycine primarily functions in the brain to reduce unwanted muscle contracts (spasticity). While glycine works in the brain, serine helps with protein synthesis, intracellular metabolism, immune system function, and muscle formation.
How does threonine impact our metabolism?
Metabolism and nutrient absorption are two important factors in our overall metabolic function. Threonine has a hand in both. On the metabolism side, it helps to regulate the way we break down fat by aiding lipotropic function. This breakdown of fat is particularly important when it occurs in the liver, preventing the buildup of fat in the liver and possibly reducing the risk of liver failure.
Threonine’s impact on nutrient absorption starts in the digestive tract. It produces a layer of gel that protects digestive enzymes. These digestive enzymes help our gut to break down nutrients from the foods we eat. This cascade of events ends with a healthy gut starts with threonine.
How much threonine do I need?
The reference daily intake (RDI) of threonine is 15 mg per kg of body weight (or roughly 6.8 mg per pound). Thus, the average 190-pound person would need to consume 1,292 mg of threonine to hit the RDI. While a number in the thousands of milligrams may seems like a lot, once you learn that six ounces of chicken breast contains 2,445 mg, the RDI becomes more attainable. A true threonine deficiency is rare in individuals that consume a balanced diet. However, given the high concentration of threonine in animal products, vegans and vegetarians may not be consuming enough threonine in their diets.
If you are looking to add more threonine to your diet, here are a few foods that have a high concentration:
- Beef- 2712 mg per 6 oz steak
- Lean chicken and turkey- 2445 mg per 6 oz chicken breast
- Tuna- 2229 mg per 6 oz fillet
- Firm tofu- 1978 mg per cup
- Boiled soybeans- 1244 mg per cup
- Milk- 706 mg per 16 oz glass
- Green peas- 322 mg per cup
- Eggs- 302 mg per 1 large egg
- GOOD IDEA beverages also contain threonine
What happens if I don’t get enough threonine?
As we mentioned before, a true deficiency is rare. However, it is possible to be consuming less than optimal quantities of this amino acid and, thus, experience low threonine levels. Symptoms of low threonine levels include muscle and memory loss, weakness and depression.
Is threonine safe?
Not only is threonine safe, but it is also an essential part of our diet. Research has shown that doses as high as four grams daily for 12 months are safe. This dosage equates to over three times the daily RDI for a 190-pound person, so there is no need to hold back on the second serving of tofu or tuna. It is possible that higher doses are also safe, there simply has not been research conducted with volumes larger than four grams. It should be noted that while threonine is generally considered safe, larger doses may have some people experiencing minor side effects, such as upset stomach, headache, nausea, or rash.
Why is it an ingredient in GOOD IDEA?
Threonine is a multifaceted ingredient in that it is necessary to help our body form collagen, elastin, and tooth enamel. These structures help to keep our muscles, bones, skin, blood vessels, tendons, digestive system, heart, and teeth healthy and strong. While a portion of our ingested threonine is dedicated to the many functions listed above, threonine can also be diverted to assist with
functions in the brain, intracellular metabolism, and immune function by way of glycine and serine. Just when you think this busy amino acid can’t work anymore, we introduce its impact on metabolic function. The ability to regulate our breakdown of fat and improve nutrient absorption plays a large role in our metabolic health. When we improve our nutrient absorption, we can help to maximize the health benefits from everything we eat. Given the impressive list of benefits and functions that can be attributed to this amino acid, it is easy to see why we chose to include threonine in every GOOD IDEA drink.
Author: Dr. Colleen Gulick, PhD (ExPhys),MS,BS (BioE),FE (ME), CSCS